Apparatus for removing clay from a foundry sand specimen



1958 H. L. JAMESON ET AL 2,355,093

APPARATUS FOR REMOVING CLAY FROM A FOUNDRY SAND SPECIMEN Filed Oct. 50, 1956 3 Sheets-Sheet l INVENTORS HOWARD L. JAMESON BY fiwwscn ,W r BALZM JL ATTO NEYS 1958 H. L. JAMESON ET AL 2,855,093

APPARATUS FOR REMOVING CLAY FROM A FOUNDRY SAND SPECIMEN Filed Oct. 30, 1956 3 Sheets-Sheet 2 FIG.2.

INVENTORS HOWARD L.-JAMESON JOSEPH E. MICKSCH BY W 5 M 19 X ATTO R N YS 1958 .H. JAMESON ETAL A 2,355,098

APPARATUS FOR REMOVING CLAY FROM A FOUNDRY SAND SPECIMEN Filed Oct. 30, 1956 3 Sheets-Sheet 3 m [32f F H64. 22 uo I INVENTORS HOWARD L. JAMESON BY JOSEPH E.MIGKSCH WW, W 7 ATTORNEYS United States Patent APPARATUS FOR REMOVING CLAY FROM A FOUNDRY SAND SPECIMEN Howard L. Jameson, Ferndale, Mich, and Joseph E. Micksch, Ashtabula, Ohio, assignors to Harry W. Dietcrt Company, Detroit, Mich., a corporation of Michigan Application October 30, 1956, Serial No. 619,207

18 Claims. (Cl. 209-499) The present invention relates to an apparatus for removing clay from a foundry sand specimen.

It is an object of the present invention to provide improved apparatus for automatically removing the clay content of molding sand from a measured specimen thereof.

More specifically, it is an object of the present invention to provide fully automatic means for repeatedly adding water to a predetermined level to sand in a receptacle, agitating the mixture of sand and water to provide for suspension of particles therein, providing a measured settling interval, and thereafter removing water from above a predetermined lower level from the receptacle.

Still more specifically, it is an object of the present invention to provide fully automatic means to control the addition and removal of water from sand in a receptacle by providing a probe sensitive to contact with the surface of the water for determining its upper level, and a siphon having an inlet at a predetermined position below said probe to determine the lower level of water.

It is a further object of the present invention, in apparatus of the character described, to provide a selfpriming siphon having a discharge leg connected to inlet and outlet legseach containing a control valve.

It is a further object of the present invention to provide compact and eificient sand washing apparatus including a support for a receptacle, a bar mounted for vertical movement on said support, a top surface probe carried by said bar, and a siphon inlet tube carried by said ibar having an inlet opening at a predetermined level .below said surface probe.

Other objects and features of the invention will become :apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, illustrating a preferred embodiment of the invention, wherein:

Figure 1 is a perspective view of the sand washing .apparatus.

Figure 2 is a view of the sand washing apparatus ex- ;ploded to expose the component parts thereof.

Figure 3 is a perspective view showing the rear of the support panel, the front of which appears in Figure 1.

Figure 4 is a simplified wiring diagram of the apparatus.

The apparatus is designed for the purpose of removing zclay from a measured specimen of foundry sand. The operation is a part of a determination of the percentage of clay. In general, the operation consists of mixing water with the sand, agitating the mixture to provide a suspension, letting the mixture settle so that heavier particles can settle out, and thereafter withdrawing the upper portion of the water and clay suspension down to a predetermined level.

The operation is a standard operation as controlled by specifications of the American Foundrymens Society. The procedure calls for the removal of all particles which settle in water at a rate of less than one inch per minute. In practice, a SO-gram sample of sand is mixed with 475 cc. of water and cc. of a standard sodium hydroxide carrier bar 40.

solution. The mixture is agitated and then allowed to settle. The settling periods and the quantity of water are standardized. The first and second settling periods are of ten minutes each and following each settling period the top five inches of Water are siphoned or otherwise drawn oif. Thereafter, the operation may be continued as long as required except that the settling periods are reduced to five minutes.

As best seen in Figure l, the apparatus comprises a support It} in the form of an open topped cabinet 11 having a removable closure 12 provided with an opening 14- therein having legs 16 for the reception of the specimen receptacle 18. The component parts of the apparatus are best seen in the exploded view of Figure 2 and the rear view of the panel as seen in Figure 3. Within the cabinet 11 is a support panel 20. Mounted on the front of the panel 20 is an electronic water level control unit 22, a timer control solenoid unit 24-, and the movable hand 26 of a timer. Also, carried at the front of the panel 20 are a plurality of relays indicated generally at 28.

At the rear of the panel, as best seen in Figure 3, there is provided the electrical timer 30 the movable hand 26 of which is'seen in Figure 2, a transformer 32, and water control connections indicated generally at 34 which will subsequently be described. Also, mounted on the back of the panel 20 is a micro switch 36 used to initiate automatic cycling of the apparatus as will presently appear.

Fixedly mounted to extend upwardly from the removable closure 12 is a rigid conduit 38 which serves as a guide andsupport for a carrier bar 40. For this purpose the conduit 38 is provided with an adjustable stop 42 thereon engageable by the carrier bar to limit its downward movement and so to predetermine its position relative to the receptacle 18. Also extending upwardly from the removable closure 12 is a guide tube 44 which is secured in an opening 46 in the closure 12. Associ ated with the guide tube 44 is a guide rod 43 fixedly secured to extend downwardly from the carrier bar 40. The rod 48 is vertically movable in guiding relation in the tube 44 and is of such length that when the bar 41 engages the stop 42, the lower end of the rod moves through the opening 46 and trips the micro switch 36 to initiate cycling of the apparatus.

Extending downwardly from the carrier bar 40 is a rigid siphon inlet tube 50 having its lower end portion turned as indicated at 52 so that when water is ejected therefrom, it acts as a nozzle and agitates the mixture of sand and water in the receptacle 18. The upper end of the tube 50 is fixed in an opening in the bar 40 and is connected to the upper end of the conduit 38 by a flexible tube 54.

Also rigidly connected to the carrier bar 40 to extend downwardly therefrom is a top surface probe element 56 which is electrically connected by suitable means such as the metal foil indicated at 58 to a conductor 60 leading to the electronic :level control device 22.

From the foregoing it will be observed that when the parts are assembled together as illustrated in Figure 1,

the bottom of the probe 56 is a predetermined distance above the opening into the lower end of the siphon tube 50 and that the vertical spacing between these elements is independent of the vertical position of the support or This is an important feature of the present invention and provides automatic means for complying with the requirements of the American Foundrymens Society for testing clay content of sand.

Referring now more particularly to Figure 3 there is provided a water inlet line 62 having a solenoid controlled inlet valve 64 therein. The inlet line 62 connects to a 'i' 65 to which is connected the outlet line 66, also controlled by a solenoid actuated outlet or drain valve 68. The third branch of the T connects f '3. line 70 leading to a T 72, a line 73, and flexible conduit 74 which is connected to the lower end of the conduit 38 previously descrihed. Connected 'to the third branch of the T 72 is a lower level control probe 76 which comprises a contact element adapted to be electrically connected to the electronic level control apparatus 22.

It may be noted at this time that the electronic level control apparatus comprises means responsive to an electrical condition, such for example as electrical capacity effective on a probe surface and includes suitable electronic elements whose details form no part of the present invention. Thus, in the'present instance 'the probes 6 and 76 may be connected in parallel so that the elfeetive electrical capacities sm'rounding the probes are additive. Under these conditions jwhen the water reaches the top level probe, the high efiective capacity of the top level probe is additive to the high effective 'capacityoi the low level probe. When the water level is intermediate the top level probe and the inlet to the siphon, the resuItant efiective capacity from the two probes is the relatively high value efiective at the lower probe 76. When the siphon has sucked air so that an air bubble surrounds the exposed area of the probe 76, then the additive capacity of the two probes is at an extremely low value. From the foregoing it 'vvill be observed that conditions exist for effecting control of a relay as follows: The relay closes when the top level of water reaches the top level probe, and remains energized asthe level of water falls until it uncovers the bottom probe, at which time the relay is de-e'nergized and remains de-energized until the top level of water again reaches the top level probe.

It is sufficient to note that the electronic level control device finally controls a relay in 'such-a way that the relay is energized when the level of water in the receptacle reaches the lower 'end of the probe '56 and remains energi'zed until a bubble of air in the T 72 reaches the surface of the probe 76 within the -T, thus signaling that the siphon tube -50 has lowered the level of water in 'the receptacle to its inlet port. At this time the relay is de energized and remains de-energi-Zed until the level of water in the receptacle again rea'chesthe'probe 56.

The cycle of operation which repeats over and over until shut off by the oper tor, will now be described. Assumin the rneasured quantity of sand in the receptacle, the outlet or drain valve -68 is "closed and the inlet valve is opened, permitting water to now i a-through the tube 50 where it mixes with the sand and produces agitation thereof causing suspension of sand and fine particles in the water. The addition of water continues until the upper level of water reaches thetop level probe 56. At this time by means which will subsequently be described, the inlet valve 64 is closed and a timer is started to provide a measured interval during which the particles in suspension may settle. After the -timer has timed out, which for the first cycle is after a ten minutes settling period, the outlet or drain valve 68 is opened. At this time since the lines 66, 70, 73, =74, 38, '54 and 50 are all filled with wa-tenthere is provided a siphon which is selfpriming and as soon as t-he valve 68 opens, siphoning starts and the top five inches of water together with all fine particles still "suspended therein is siphoned ofi. As soon as the level of water reaches the inlet .port at the bottom of the siphon 'tube 50, air 'isdrawninto the systern and a bubble of air reaches the T 72 where it exeludes water fro'm the-exposed area of the bottom level probe 76. This has the effect of energizing the'electrdnic level control relay, which closes the valve 158, opens the valve'64, and}starts the second cycle. This'cycle is automatically repeated over and over with the :exception of one change which takes place following the second cycle.

The timing'means isof the'type including a motor and clutchf-the motor driving the indicating 'hand 26 when his clutched thereto and also controlling-switch contacts as will subsequently be described in thewiring diagram.

The timer includes a fixed post and a resilient return spring is connected to the hand 26 so that when the clutch is de-energized the "hand 26 returns to starting position against the post 80. After two cycles have been completed a movable stop pin 82 is advanced by spring means (not shown) into position to be engaged by the hand 26 as it is returned by its spring when its clutch is disengaged. During the first two cycles of the machine the pin is retained in retracted position by a solenoid 84. After the completion of the second cycle the solenoid is tic-energized and the spring projects the pin into the path of the hand 26. Thereafter, the hand is not permitted to return to its initial starting position but instead returns to an intermediate starting position so that it will time out after a reduced cycle. In practice, the first two settling periods are of ten minutes duration and succeeding settling periods are of five minutes duration.

Referring now to the wiring diagram there is provided a main control switch closure of which energizes a pilot light 92, and a transformer 32 which powe'rs the electronic level control device 22. The details of the automatic level control are not included herein but it is effective to energize and dc-energize a relay 98 adapted to control a switch 100. The micro switch 36 which is closed by movement of the support bar to operative position, includes a main circuit control arm 102 "adapted to energize the control circuit generally, and an electronic level control arm 104 making contact with a line 106 which in practice is connected to the electronic control device 22 The electric timer includes a timer motor 108 and a relay 110 controlling the clutch connecting the motor to the indicating hand 26 and the switch mechanism. T he electric timer switch includes switch arms 112 and 114. The solenoid of the drain or outlet valve 65, is indicated at 116, and the solenoid of the inlet valve '64'is indicated at 118. "The manually controlled no-fill? switch is indicated at 120 andalso appears inFigure l.

Relays 122, 124 and 126 are provided and the relay $4 of the timer control solenoid is "indicated in the figure. Relay 122 controls switch "a'rrns 128 and 13:0. Relay 124 controls 'switch 'arms 1327and 134. Relay 1236 controls switch arms 136 and 138.

With the foregoing general 'clescri tio oi the "circuit the operation will be briefly described. The succeeding operation will have been brought to a "close by opening the no-fill switch 120 whichwillte'rminate cycling of the machine after "com letion of a washcy'cleanu prcsumably thereafter the power switch '90 will have been opened. The micro switch 36 will be open so long as the support bar 40 is in upper position. The receptacle '18 will not be filled with water, and accordingly the 'clccironic level control relay '98 will be do-energized and its switch arm in its lowermost position as illustrated in the figure. At this time the operator may close the no-fill switch 120 and the power switch 90. With a recepta'cle with the measured quantity of sand therein placed on the support 16, fthesupp'ort bar 40 is moved downwardly into engagement with the stop 42, thereby positioning the probe 56 within the receptacle and also closing the micro switch Closure or the micro switch 36 closes a circuit through .the switch arm "to the 'clcctronic level control and also completes a'circu'it through the "switch arm 102 which in general provides for completion of the various "coiitrolcircuits as will now be described.

In the first place a Circuit is completed through the switch arm '112 to the 'timer motor 108. However, the "relay controlling the timer clutch is dc-energized so that the timing interval is not started.

Closure of the switch arm 102 completes a circuit through the no-fill switch and the"solenoid 118 of the inlet valve 64 and accordingly, waterflows into the receptacle. This continues until the upper'level of water reaches the .probe 56 at which time the relay '98 is energized and shifts the control arm 100 upwardly to complete a circuit to the timer clutch 110. This initiates a timing cycle which in this instance will be ten minutes. In addition, upward movement of the arm 100 breaks the circuit to the solenoid 118 of the inlet valve and accordingly inflow of water is terminated.

At the conclusion of the predetermined interval as timed by the timer 30 the timer switch operates to shift the switch arms 112 and 114 downwardly. Downward movement of the'switch arm 112 completes a circuit to the drain valve solenoid 116 and accordingly, siphoning off of the water in the receptacle immediately commences. At the same time, downward movement of switch arm 114 completes a circuit through the switch arm 134 through the relay 122 thereby shifting switch arms 128 and 130 downwardly. Downward movement of the switch arm 128 completes a holding circuit through the relay 122 and downward movement of the switch arm 130 prepares a circuit for subsequent operation.

After the top five inches of water have been siphoned off from the receptacle, the siphon sucks air and the air bubble surrounds the exposed area of the probe 76 in the T 72 which de-energizes the electronic level control relay 98 causing its switch arm 100 to move downwardly to complete a circuit through the solenoid 118 of the inlet valve 64, thus initiating a second cycle. At the same time, downward movement of the switch arm 100 de-energizes the clutch relay 110 permitting the spring means to move the switch arms 112 and 114 upwardly to the position shown in Figure 4. This has the efiect of completing a circuit through the switch arm 114, the switch arm 138, and the switch arm 130 which at this time engages the contact 140 by reason of the holding circuit through the relay 122. This shifts the switch arms 132 and 134 downwardly establishing a holding circuit through the relay 124 and maintaining the switch arm 134 in engagement with the contact 142.

As soon as the level of water in the receptacle reaches the top level probe, relay 98 is again energized shifting the switch arm 100 upwardly to start a second timing cycle, upon the completion of which timer switch arms 112 and 114 move downwardly. Downward movement of the timer switch arm 112 again opens the drain valve by energizing drain valve solenoid 116. At this time downward movement of the switch arm 114 completes a circuit through switch arm 134 and contacts 142 through the relay 126. Energization of the relay 126 moves the switch arms 136 and 138 downwardly. Downward movement of the switch arm 136 deenergizes solenoid 84 and releases the stop pin 82 for movement into the path of the timer hand 26. Thereafter the cycle is repeated over and over without variation except that the timing interval is now of decreased duration by reason of the pin 82 preventing full return movement of the timer hand 26.

When the operator determines that the fine suspended material has been removed from the specimen, the nofill switch is opened. This has no immediate effect and permits the cycling to continue up to the point where water is siphoned off-from the receptacle and the refilling of the receptaclewould normally be initiated. At this time the receptacle with the sand and water remaining therein is removed, the water removed from the sand, and the sand weighed to determine by loss of weight the quantity of .clay which was originally included therein.

The drawings and the foregoing specification constitute a description of the improved automatic sand washer in such full, clear, concise and exact terms as to enable any I 6 addition means for adding water to said receptacle, agitating means for agitating the mixture in said receptacle to cause suspension of fine particles in the water, water withdrawal means for withdrawing water and particles suspended therein from the mixture above a predetermined level therein, automatic control means for actuating said water addition means and said agitating means to fill said receptacle to a predetermined level and for agitating said mixture, and timing means for providing a measured interval for settling of particles and thereafter initiating operation of said water withdrawal means to lower the water to a predetermined level. v

2. An automatic apparatus for removing clay from a measured specimen of foundry sand or the like comprising a receptacle for containing sand and water, water addition means for adding Water to said receptacle, said addition means including agitating means for agitating the mixture in said receptacle to cause suspension of fine particles in the water, water withdrawal means for withdrawing water and particles suspended therein from the mixture above a predetermined level therein, automatic control means for actuating said water addition means and said agitating means to fill said receptacle to a predetermined level and for agitating said mixture, and timing means for providing a measured interval for settling of particles and thereafter initiating operation of said water withdrawal means to lower the water to a predetermined level, said automatic control means being responsive to the Water level reaching a predetermined minimum for terminating operation of said water withdrawal means and initiating operation of said water addition means and agitating means.

3. An automatic apparatus for removing clay from a measured specimen of foundry sand or the like comprising a receptacle for containing sand and water, water addition means for adding water to said receptacle, said addition means including agitating means for agitating the mixture in said receptacle to cause suspension of fine particles in the water, water withdrawal means for withdrawing water and particles suspended therein from the mixture above a predetermined level therein, automatic control means for actuating said water addition means and said agitating means to fill said receptacle to a predetermined level and for agitating said mixture, and timing means for providing a measured interval for settling of particles and thereafter initiating operation of said water withdrawal means to lower the water to a predetermined level, said automatic control means being responsive to the water level reaching a predetermined minimum for terminating operation of said water withdrawal means and initiating operation of said water addition means and agitating means, said automatic control means being responsive to the level of water reaching a predetermined maximum for terminating operation of said water addition and agitating means and starting said timmg means.

4. Apparatus as defined in claim 3 in which said water addition and agitating means comprises a nozzle arranged to discharge water forcibly into said receptacle.

5. Apparatus as defined in claim 3 in which said water withdrawal means comprises a siphon with its intake dis-- posed at a predetermined distance below the maximum water level in said receptacle.

6. Apparatus as defined in claim 3 in which the water addition and withdrawal means together comprise a first tube having an open end adapted to be disposed within said receptacle at a fixed level therein, a second tube extending vertically outside said receptacle and connected at its upper end to the upper end of said first tube, the lower end of said second tube being below the open lower end of said first tube, supply and drain lines connected to the lower end of said second tube, and valves in said lines operable to supply water when the valve in said supply l ne is open and the valve in said drain 7 line is closed, and to initiate siphoning when the valve in said drain line is open and the valve in said supply line is closed.

7. Apparatus as defined in claim 3 in which said automatic control means comprises top and bottom probes responsive to movement of water level thereto.

8. In apparatus of the character described comprising a receptacle, means for adding water to the receptacle to a predetermined level and for removing water to a second lower predetermined level, comprising a first tube having an open end adapted to be disposed within said receptacle at said second lower predetermined level therein, a second tube extending vertically outside said receptacle and connected at its upper end to the upper end of said first tube, the lower end of said second tube being below the open lower end of said first tube, supply and drain lines connected to the lower end of said second tube, and valves in said lines operable to supply water when the valve in said supply line is open and the valve in said drain line is closed, and to initiate siphoning when the valve in said drain line is open and the valve in said supply line is closed.

9. In apparatus of the character described comprising a receptacle, ineans for adding water to the receptacle to a predetermined level and for removing water to a second lower predetermined level, comprising a first tube having an open end adapted to be disposed within said receptacle at said second lower predetermined level therein, a second tube extending vertically outside said receptacle and connected at its upper end to the upper end of said first tube, the lower end of said second tube being below the open lower end of said first tube, supply and drain lines connected to the lower end of said second tube, and valves in said lines operable to supply water when the valve in said supply line is open and the valve in said drain line is closed, and to initiate siphoning when the valve in said drain line is open and the valve in said supply line is closed, said first tube having its lower end portion inclined to induce turbulence in water in the receptacle.

10. In apparatus for removing clay from a measured specimen of foundry sand or the like, a support, a receptacle for sand and water positioned on said support, a first vertical conduit fixedly mounted on said support to extend upwardly therefrom, a transverse bar movable vertically on said conduit, a second conduit fixedly mounted on said bar and extending downwardly therefrom and movable into the open end of said receptacle, stop means on said first conduit engagea-ble by said bar to determine the spacing of the lower end of said second conduit from the bottom of said receptacle, a flexible tube connecting the upper ends of said conduits and means for supplying and drawing off water through said conduits and tube.

'11. Apparatus for removing clay from a measured specimen of foundry sand or the like comprising a 'support, a receptacle for sand and water positioned on said support, a first vertical conduit on said support, a transverse bar movable vertically on said conduit, a second conduit extending downwardly from said bar and movable into the open end of said receptacle, stop means on said first conduit engageable'by said bar to determine the spacing of the lower end of said second conduit from the bottom of said receptacle, and la flexible tube connecting the upper ends of said conduits, 'a probe depending from said bar and movable into the receptacle, said probe comprising part of a water level :sensitive device and being positioned a predetermined distance above the open end of said second tube.

12. Apparatus for removing clay from a measured specimen of foundry sand or the like comprising a support, a receptacle for sand and water positioned :on said support, a first vertical conduit on said support, a trans verse bar movable vertically on said conduit, a second ond it extending ownwardly from said. bar and movable into the open end. ot said receptacle, stop means on said first mnduit engageable by said'ba'r to' determine the Spacing of the lower end of said second conduitfrom the bottom of said. receptacle, and a flexible tube con necting the upper ends'of said conduits, a probe depending from Said bar and movable intov the receptacle, said prQ'be comprising .part of a wa-ter'level sensitive device and bemglipositi'oned a predetermined distance "above the openqend of said second tube, said second tube being connected to operate as the inletto a siphon system so as to drain water to a level in said receptacle determined by. the location therein of its open end.

13. Apparatus for removing clay from a measured specimen of foundry sand or the like comprising a support/a receptacle for sand and water posi'toned on said support, a vfirst vertical conduit on said support, a transverse bar movable vertically on said conduit, a second conduit extending downwardly from said bar and movable into the open end of said receptacle, stop means on said first conduit'en gageable by said bar to determine the spacing of the lower end of said second conduit from the bottom of said receptacle, and a flexible tube connecting the upper ends of said conduits, a probe depending iirom s-aid bar and movable into the receptacle, said probe comprising part of a water level sensitive device and being positioned a predetermined distance above the open end or said second tube; said second tube being connected to operate as the inlet, to 'a siphon system so as to drain water to a level in said receptacle determined by the location therein of its open end, the relative posit-ion of said second tube and probe being fixed so that a fixed difference, in water 'level is eflFective thereon irrespective of the exact position of said receptacle.

14. Apparatus for removing clay from a measured specimen of foundry sand or the like comprising a support, a receptacle for sand and water positioned on said support, a first vertical conduit on said support, a transverse bar movable vertically on said conduit, a second conduit extending downwardly from said bar and movable into the open end of said receptacle, stop means on said first conduit engageable by said bar to determine the spacing of the lower end of said second conduit from the bottom of said receptacle, a flexible tube connecting the upper ends of said conduits, a guide tube extending upwardly from said support, a guide rod fixed to said bar and movable in said guide tube and adapted to extend below said support when said bar is in lowermost position, and an automatic control circuit for said apparatus including a switch below said support in position to be engaged by said rod.

15. Apparatus for removing clay from a measured specimen of foundry sand or the like comprising a receptacle for sand and water, automatic means for adding water to a predetermined upper level therein, timing means 'for providing a settling period, means operated by said timingmeans to drain water from above a predetermined lower level in said receptacle, said automatic means being responsive to the water level reaching its lower value for refilling the receptacle.

l6. Apparatus for removing clay from a measured specimen of foundry sand or the like comprising a receptacle for sand and water, automatic means for adding water to a predetermined upper level therein, timing means for providing a settling period, means operated by said timing means to drain water from above a predetermined lowerlevel 'in said receptacle, said automatic means being responsive to the water level reaching its lower value for refilling the receptacle, Said timing means being automatically started by the water level reaching its upper level.

17. Apparatus for removing clay from a measured specimen of foundry sand or the like comprising a receptacle for sand and water, automatic means for adding water to a predetermined upper level therein, timing means for providing a settling period, means operated by said timing means to drain water from above a predetermined lower level in said receptacle, said automatic means being responsive to the water level reaching its lower value for refilling the receptacle, said timing means being automatically started by the water level reaching its upper level, said timing means and said automatic means being alternately operable to fill and drain said receptacle until turned olf by an operator.

18. Apparatus for removing clay from a measured specimen of foundry sand or the like comprising a receptacle for sand and water, automatic means for adding water to a predetermined upper level therein, timing means for providing a settling period, means operated by said timing means to drain water from above a predetermined References Cited in the file of this patent UNITED STATES PATENTS 2,085,007 Conrath June 29, 1937 2,752,227 Weiland June 26, 1956 2,779,189 Corneil Jan. 29, 1957 

